1. Field of the Invention
The present invention relates to an image pickup apparatus.
2. Description of the Related Art
Photometry and focus detection are started after mirror-down driving is completed in a single-lens reflex camera. In order to improve the precisions of the photometry and focus detection, they need to start after mirror's bounds sufficiently attenuate. However, it is difficult to directly detect the mirror's bounding state, and prior art start the photometry and focus detection when a time period passes which is assumed sufficient to attenuate the mirror's bounds after mirror-down driving starts (Japanese Patent Laid-Open No. 2000-137287).
A time period within which the mirror's bounds sufficiently attenuate regardless of a state of a camera is set to the above time period from when the mirror-down driving starts to when the mirror's bounds attenuate. However, the time period enough to attenuate the mirror's bounds varies according to the power-supply voltage of the camera or the environmental temperature used for the camera.
For example, a time period enough to sufficiently attenuate the camera's bounds needs to be set to a camera in which the power-supply voltage of the camera is the lowest operable voltage of the camera. Hence, as the power-supply voltage of the camera becomes higher, it is necessary to wait for a set time period although the mirror bounds have already attenuated, deteriorating a consecutive shooting speed (frame rate).